/*
 * simple test of swappin with anonymous shared mmaping
 * cw@f00f.org
 */

#include <unistd.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>

/* must be >= physical memory size */
#define	MS	((768+10)*1024*1024)

int	main()
{
	char	*buf;
	size_t	ps;
	size_t	i;
	int	status;
	
	if(0 >= (ps = getpagesize())){
		perror("getpagesize");
		return	1;
	}
	if((char*)-1 == (buf = mmap(NULL,MS,PROT_READ|PROT_WRITE,MAP_SHARED|MAP_ANON,-1,0))){
		perror("mmap");
		return	1;
	}

	/* verify child and modify pages and parent will see these changes */
	for(i=0;i<ps;buf[i++]=1);
	if(fork()){
		if(-1 == wait(&status)){
			perror("wait");
			return	1;
		}
		if((123 != WEXITSTATUS(status)) && WIFEXITED(status)){
			fprintf(stderr,"Wrong exit code!\n");
			return	1;
		}
	}else{
		for(i=0;i<ps;buf[i++]=2);
		return	123;
	}
	for(i=0;i<ps;++i){
		if(2 != buf[i])
			break;
	}
	if(i < ps){
		fprintf(stderr,"Parent couldn't see child modifications (%d/%d)\n",i,ps);
		return	1;
	}else
		fprintf(stderr,"Parent COULD see child modifications\n");

#if 0
	/* touch pages -- swap swap swap */
	for(i=0;i<MS;i+=ps)
		buf[i] = 0;
#endif

	return	0;
}